Mitochondrial, acidic and cytosolic pHs determination by 31P NMR spectroscopy: design of new sensitive targeted pH probes
Abstract
31P Nuclear magnetic resonance (NMR) is a unique technique to monitor noninvasively the energetics of living systems at real time through the detection of a variety of phosphorylated metabolites. Using adequately designed ax-aminophosphonates as external probes, we have shown earlier that 31P NMR can also give access simultaneously to the accurate pH of cytosolic and acidic comptartments in normal and stressed cultured celles or isaolated perfused organs, a feature that was not possible using endogenous inorganic phosphate as the probe. More recently, we obtained a series of derivatives of these new pH probes that incorporate a triphenylphosphonium cation as a specific vector the the mitochondrion. Here, we describe the synthesis, 31P NMR pH titrating properties in buffers, and application in cultures of the green alga Chlamydomonas reinhardtii of two of these mitochondria-targeted pH probes in comparison with one nonvectorized, yet still informative ax-aminophosphonate.